[98_1LE]

First off let me say I am missing about 10 receipts, all in-town, which would pull the average down since the road trip receipts are included.

That out of the way, for the 39 receipts I have, the green Z28 has averaged just over 22mpg, thats right, twenty two. The high is 30.4 (all interstate), low 16.2 (hot rodding it with a/c blasting). For the most part I don't beat on it, but frequently accelerate quickly (shift point <= 4k).

As for the missing receipts, assuming the car averaged 20mpg for those 3000 miles (300 per fillup), which gets the odometer very close, it still has close to 21.6mpg. Not bad for a pushrod dinosaur. Only mods are a "lid" and Nitto drag radials. It has 96k miles.

[gunslinger]

I used to get 30 mpg on the highway stock and 16 in the city. After headers, my mileage went down significantly. With tuning I was able to get some of that back on the highway and do better then stock in the city. Now I get about 18mpg city and there is not enough non-traffic highway around DC to get accurate highway mileage.

I got about 28 MPG on my last road trip with my stock 1998 M6 Z28, all interstate driving, some hills. I had Mac's awhile ago, but had to change back to the stock exhaust manifolds for the SMOG test.

I did notice that Mac's decreased my mileage( never had money for a tune) on the stock tune, but I always thought that a tune could bring ALL the mileage back as long as I was light on the gas pedal (interstate driving at 75MPH ONLY!). I guess when you increase power, you have to use more fuel, no matter if the gas flow in and out of the combustion chamber has increased.

Anyway, I wish I could keep my Mac's on my car all the time and not have to change headers->manifolds every 2 years.... Damn Kalifornia!! Nicest Weather in the US, crappiest laws in the US!

This post has been edited by gunslinger: Jul 12 2007, 03:59 PM